Scholastic - Scholastic provides many different lesson plans, strategies, and tools for teachers. Lesson plans are available for all ages and subjects.
TeAchnology - With over 30,000 lesson plans, TeAchnology is an excellent source of lesson plans on a wide range of subjects. The site also provides over 7,500 printable worksheets.
Discovery Education - Discovery Education provides hundreds of lesson plans and other tools. The site's original lesson plans were designed by teachers for teachers.
Smithsonian Education - Smithsonian Education provides teachers with lesson plans on an array of subjects--from art and design to language arts.
LessonPlanz - LessonPlanz is a search engine for lesson plans. The site also links to books, activities, and other teaching aids.
Chalksite - Chalksite is a free online suite of tools for teachers who want to connect with parents and students through the web. Teachers can use it to post grades, assignments, discussions, and messages.
Education World - This site provides teachers with customizable templates and tools. A few of the templates teachers can find include starting blocks for assessments, calendars, awards, bulletin boards, and organizers.
ClassMarker - ClassMarker is an online testing tool that can be used to create quizzes and tests online. The tool also grades tests so you don't have to.
SlideShare - This creative web app makes it easy to upload PowerPoint presentations and share them online. SlideShare works especially well for assignments, webinars, and parent-teacher conferences.
Evernote - Evernote is a bookmarking and note taking web app that can be synced with mobile devices--perfect for teachers who want to be able to create, manage, and share notes from anywhere.
FlashcardExchange - The FlashcardExchange provides teachers with tools to create flashcards. Once created, the cards can be printed or shared with students online.
4Teachers.org - This resourceful website provides teachers with several different tools to use in the classroom, including a Note Star, Think Tank, and Web Poster Wizard.
PBS Teachers - PBS Teachers offers interactive studies, activity packs, development classes, and other useful resources for elementary school teachers.
Tools for Educators - This site offers free worksheets, worksheet creators, and a table wizard. Teachers can also use the site to create word searches, board games, and more.
TeacherTube - Teachers can find instructional videos from other teachers on TeacherTube. The site can also be used to post instructional videos for students.
Elementary Education - The About.com Guide to Elementary Education provides a huge collection of resources for elementary educators. Resources include tips, lesson plans, forums, and an educational blog.
RefDesk - The RefDesk is an online tool that can be used to find facts, news, and reference materials. Other site features include a calendar, currency converter, and calculator.
The Clever Sheep - This site provides podcasts to assist teachers in integrating technology into the classroom through e-learning, websites, and web apps. Each episode lasts seven to ten minutes. New episodes are published weekly.
Time for Kids - The Time for Kids Teachers' Edition provides current news appropriate for K-6 students. This is a great site for elementary teachers who want to keep children up-to-date on current events around the world.
Awesome Stories - Awesome Stories provides information about films, trials, natural disasters, history, and biographies in addition to stories from historical sources.
Guest post from Karen Schweitzer, the About.com Guide to Business School. Karen also writes for OnlineDegreePrograms.org, an online degree program resource.
Photo credit: jmacphoto